Higurashi-Satoko: I always feel sorry for her sense her hole clan was always hated, she killed her own parents, beaten to a plump by Shion with a book, her bother has a virus and he doesn't really have a chance on being ceared, her uncle beats her to death, and in one episode she got stabbed to death by Mion!

Tetsu-Peace maker:Watching your parents die in front of you and getting mentally scarred for life, almost killed by your friend, ear almost cut in half, knew the guy you killed didn't kill your parents...

Naoya-Night Head Genesis:Trust me he really, really, really tells you not to wish to read people minds... and thats all I have to say about him.

All I can think of thats not towards Naruto and the bad childhoods. XD

well, i think Enma Ai from Jigoku Shoujo. Her life ended when she only 7 years old just becuz her village believed that sacrificing a young girl who just turned 7 would make their harvest better.... Then she was forced to become the Hell Girl. If she refused then her loved ones will suffer for whole eterninty and that if she doesn't do her job every thing that she hold dear to her heart will perish. She had to take people to hell whether if they didn't do something wrong for 400 years.

And even maybe Akito/Agito from Air gear. Man, his own brother used him as a weapon. and his own best friend betrayed him. No wonder he has 2 personalities

Sasuke Uchiha from Naruto. He watched his beloved brother kill the whole Uchiha clan in one night. Itachi even tried to kill him.

And defenently Lucy from Elfen Lied. God, she had a really sad and bloody childhood. I'm not suprised that she bacame a murderer. I would have done the same thing. If someone would even dare hurt my dog, i'll rip their hearts out in an instant.

Lucy from elfen lied because.. well other people had already stated why.. n i can't be bothered.

And pardon me for being very unoriginal abt this but, Gaara:

Dude is a monster from birth
Got no friends
His dad wants to kill him
The only guy he thought cares about him betrays him
That same guy told him his mom died hating him
Before blowing up to pieces and try to kill him as well

lol if i was him i'd be an emo too.. that's some hardcore emo stuff in there